Thousands of fans turned out on Saturday for the first Formula E electric car race in the United States, with organizers saying the event along downtown Miami's bayfront would help boost more energy efficient mainstream automobile technology.

"Formula E will pioneer technology which will be used on normal road cars," British entrepreneur Richard Branson, the Virgin Racing team owner, told a press conference before the race.

"I hope 10 years from now the smell of exhausts from cars will be a thing of the past as much as the smell of cigarettes in restaurants," added Branson, whose Virgin Group sponsors a two-car team.

Miami is the fifth of 10 cities around the world to host races for the inaugural year of the Formula E championship, launched in Beijing in September 2014.

So far, Formula E has offered the same, albeit quieter, thrills as the popular Formula One events, with low-slung, open-wheeled cars capable of speeds up to 136 miles per hour (219 kilometers per hour).

The cars give off a high-pitched whistling sound, a bit like a dentist's drill.

The Federation Internationale de l'Automobile (FIA), which organizes the races and also oversees Formula One, has attracted sponsors such as tire maker Michelin and courier service DHL, hoping the series will help the development of mainstream electric cars.

"The technology improves unbelievably once these large companies start investing in research," said Pier Luigi Ferrari, the managing director of DHL motorsports.

All the cars have an identical chassis and drivetrain, as well as a massive lithium ion battery that makes up one third of the car's weight. The limited battery life forces drivers to change cars mid-race into a second, fully charged car.

The series will become an open championship next year, allowing eight manufacturers to pursue their own designs. They will be limited at first to the drivetrain; the e-motor, the inverter, the gearbox and the cooling system.

All other elements will remain the same to prevent costly competition over aerodynamic design.

Branson said he was excited by the technology advances that he predicted would come out of Formula E, such as increased battery energy density, more efficient drive trains, and wireless "inductive" charging systems.

"Every team next year will be working hard to beat each other and all that manpower, finance and energy will produce breakthroughs and make a big difference to normal battery-driven cars," he said.

Saturday's race was won by e.dams-Renault driver Nicolas Prost, a Frenchman and son of former Formula 1 great Alain Prost.